Scope repository and CI to ruby feature only

[Copilot]

This PR narrows the repository to the ruby feature so CI/test runtime is spent only on Ruby-relevant paths. Non-ruby feature content and workflows are removed, and remaining workflows are constrained to Ruby.

• Repository scope reduction

  • Removed all non-ruby feature directories under src/ and test/.
  • Kept only src/ruby and test/ruby as the maintained feature/test surface.

• CI workflow narrowing

  • Simplified feature test matrices in test-all.yaml to ruby only.
  • Simplified PR change-detection in test-pr.yaml to watch only ruby paths and removed non-ruby conditional jobs/exclusions.
  • Updated manual test workflow defaults (test-manual.yaml) to run ruby by default.
  • Removed workflows dedicated to non-ruby feature maintenance/testing.

• Documentation alignment

  • Updated README.md examples and repo structure to reflect a ruby-only feature collection.

# .github/workflows/test-all.yaml
strategy:
  matrix:
    features: ["ruby"]

[Copilot]

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[fulldecent]

@copilot update this so that the GitHub Actions will run. i am reviewing this PR now and the actions did not run

[Copilot]

@copilot update this so that the GitHub Actions will run. i am reviewing this PR now and the actions did not run

Updated in commit 5ee41e4. I changed .github/workflows/test-pr.yaml so PR workflows always run ruby tests directly (no change-detection gating), which ensures GitHub Actions run on pull requests.

[fulldecent]

@copilot

i ran it and

---

test-scenarios (ruby)
Started 9m 46s ago

runs and runs and I see absolutely nothing in github actions. so I killed it

this is not working

[Copilot]

@copilot

i ran it and
...

Fixed in commit 2365e9a. test-scenarios was assigned to devcontainer-image-builder-ubuntu, but that runner was not available for this PR run (no steps started, runner_id 0). I changed it to ubuntu-latest so the job starts normally and shows logs.